diff options
| -rw-r--r-- | mm/zswap.c | 189 |
1 files changed, 121 insertions, 68 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 1692273ff08c..d6b1e81860b9 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -410,6 +410,12 @@ static int __must_check zswap_pool_tryget(struct zswap_pool *pool) return percpu_ref_tryget(&pool->ref); } +/* The caller must already have a reference. */ +static void zswap_pool_get(struct zswap_pool *pool) +{ + percpu_ref_get(&pool->ref); +} + static void zswap_pool_put(struct zswap_pool *pool) { percpu_ref_put(&pool->ref); @@ -1403,68 +1409,38 @@ resched: /********************************* * main API **********************************/ -bool zswap_store(struct folio *folio) + +static ssize_t zswap_store_page(struct page *page, + struct obj_cgroup *objcg, + struct zswap_pool *pool) { - swp_entry_t swp = folio->swap; - pgoff_t offset = swp_offset(swp); - struct xarray *tree = swap_zswap_tree(swp); struct zswap_entry *entry, *old; - struct obj_cgroup *objcg = NULL; - struct mem_cgroup *memcg = NULL; - - VM_WARN_ON_ONCE(!folio_test_locked(folio)); - VM_WARN_ON_ONCE(!folio_test_swapcache(folio)); - - /* Large folios aren't supported */ - if (folio_test_large(folio)) - return false; - - if (!zswap_enabled) - goto check_old; - - /* Check cgroup limits */ - objcg = get_obj_cgroup_from_folio(folio); - if (objcg && !obj_cgroup_may_zswap(objcg)) { - memcg = get_mem_cgroup_from_objcg(objcg); - if (shrink_memcg(memcg)) { - mem_cgroup_put(memcg); - goto reject; - } - mem_cgroup_put(memcg); - } - - if (zswap_check_limits()) - goto reject; /* allocate entry */ - entry = zswap_entry_cache_alloc(GFP_KERNEL, folio_nid(folio)); + entry = zswap_entry_cache_alloc(GFP_KERNEL, page_to_nid(page)); if (!entry) { zswap_reject_kmemcache_fail++; goto reject; } - /* if entry is successfully added, it keeps the reference */ - entry->pool = zswap_pool_current_get(); - if (!entry->pool) - goto freepage; + /* zswap_store() already holds a ref on 'objcg' and 'pool' */ + if (objcg) + obj_cgroup_get(objcg); + zswap_pool_get(pool); - if (objcg) { - memcg = get_mem_cgroup_from_objcg(objcg); - if (memcg_list_lru_alloc(memcg, &zswap_list_lru, GFP_KERNEL)) { - mem_cgroup_put(memcg); - goto put_pool; - } - mem_cgroup_put(memcg); - } + /* if entry is successfully added, it keeps the reference */ + entry->pool = pool; - if (!zswap_compress(&folio->page, entry)) - goto put_pool; + if (!zswap_compress(page, entry)) + goto put_pool_objcg; - entry->swpentry = swp; + entry->swpentry = page_swap_entry(page); entry->objcg = objcg; entry->referenced = true; - old = xa_store(tree, offset, entry, GFP_KERNEL); + old = xa_store(swap_zswap_tree(entry->swpentry), + swp_offset(entry->swpentry), + entry, GFP_KERNEL); if (xa_is_err(old)) { int err = xa_err(old); @@ -1481,11 +1457,6 @@ bool zswap_store(struct folio *folio) if (old) zswap_entry_free(old); - if (objcg) { - obj_cgroup_charge_zswap(objcg, entry->length); - count_objcg_events(objcg, ZSWPOUT, 1); - } - /* * We finish initializing the entry while it's already in xarray. * This is safe because: @@ -1501,32 +1472,114 @@ bool zswap_store(struct folio *folio) zswap_lru_add(&zswap_list_lru, entry); } - /* update stats */ - atomic_long_inc(&zswap_stored_pages); - count_vm_event(ZSWPOUT); - - return true; + /* + * We shouldn't have any possibility of failure after the entry is + * added in the xarray. The pool/objcg refs obtained here will only + * be dropped if/when zswap_entry_free() gets called. + */ + return entry->length; store_failed: zpool_free(entry->pool->zpool, entry->handle); -put_pool: - zswap_pool_put(entry->pool); -freepage: +put_pool_objcg: + zswap_pool_put(pool); + obj_cgroup_put(objcg); zswap_entry_cache_free(entry); reject: + return -EINVAL; +} + +bool zswap_store(struct folio *folio) +{ + long nr_pages = folio_nr_pages(folio); + swp_entry_t swp = folio->swap; + struct obj_cgroup *objcg = NULL; + struct mem_cgroup *memcg = NULL; + struct zswap_pool *pool; + size_t compressed_bytes = 0; + bool ret = false; + long index; + + VM_WARN_ON_ONCE(!folio_test_locked(folio)); + VM_WARN_ON_ONCE(!folio_test_swapcache(folio)); + + if (!zswap_enabled) + goto check_old; + + objcg = get_obj_cgroup_from_folio(folio); + if (objcg && !obj_cgroup_may_zswap(objcg)) { + memcg = get_mem_cgroup_from_objcg(objcg); + if (shrink_memcg(memcg)) { + mem_cgroup_put(memcg); + goto put_objcg; + } + mem_cgroup_put(memcg); + } + + if (zswap_check_limits()) + goto put_objcg; + + pool = zswap_pool_current_get(); + if (!pool) + goto put_objcg; + + if (objcg) { + memcg = get_mem_cgroup_from_objcg(objcg); + if (memcg_list_lru_alloc(memcg, &zswap_list_lru, GFP_KERNEL)) { + mem_cgroup_put(memcg); + goto put_pool; + } + mem_cgroup_put(memcg); + } + + for (index = 0; index < nr_pages; ++index) { + struct page *page = folio_page(folio, index); + ssize_t bytes; + + bytes = zswap_store_page(page, objcg, pool); + if (bytes < 0) + goto put_pool; + compressed_bytes += bytes; + } + + if (objcg) { + obj_cgroup_charge_zswap(objcg, compressed_bytes); + count_objcg_events(objcg, ZSWPOUT, nr_pages); + } + + atomic_long_add(nr_pages, &zswap_stored_pages); + count_vm_events(ZSWPOUT, nr_pages); + + ret = true; + +put_pool: + zswap_pool_put(pool); +put_objcg: obj_cgroup_put(objcg); - if (zswap_pool_reached_full) + if (!ret && zswap_pool_reached_full) queue_work(shrink_wq, &zswap_shrink_work); check_old: /* - * If the zswap store fails or zswap is disabled, we must invalidate the - * possibly stale entry which was previously stored at this offset. - * Otherwise, writeback could overwrite the new data in the swapfile. + * If the zswap store fails or zswap is disabled, we must invalidate + * the possibly stale entries which were previously stored at the + * offsets corresponding to each page of the folio. Otherwise, + * writeback could overwrite the new data in the swapfile. */ - entry = xa_erase(tree, offset); - if (entry) - zswap_entry_free(entry); - return false; + if (!ret) { + unsigned type = swp_type(swp); + pgoff_t offset = swp_offset(swp); + struct zswap_entry *entry; + struct xarray *tree; + + for (index = 0; index < nr_pages; ++index) { + tree = swap_zswap_tree(swp_entry(type, offset + index)); + entry = xa_erase(tree, offset + index); + if (entry) + zswap_entry_free(entry); + } + } + + return ret; } bool zswap_load(struct folio *folio) |